Adam Aquino

Automated Guided Vehicles:
Hardware
By: Adam Aquino
November 7, 2014
Review
• An automated guided vehicle or automatic
guided vehicle (AGV) is a mobile robot that
follows markers or wires in the floor, or uses
vision, magnets, or lasers for navigation. They are
most often used in industrial applications to
move materials around a manufacturing facility or
warehouse. (Wikipedia)
• Used in every industry (large factories and
storage)
• Paper, metals, newspaper, general manufacturing etc.
Questions to Consider
• Why would certain types of AGVs be preferable
over others?
• What scenarios are the most appropriate for
certain types of AGVs?
Overview: History and Current State
• First AGV invented by Barrett Electronics
in 1954. The term was not introduced until
the 1980’s, but was previously known as
driverless vehicles.
• The first model was a modified towing tractor
that followed an imbedded wire in the floor.
Sensors on the bottom of the tow truck sensed
and responded to a magnetic field from the
wires.
Overview: History and Current State
• Today, the most advanced AGVs
are laser navigated (LGV), which
are sophisticated and capable of
communicated with other robots.
Many are navigated using machine
vision as well.
Ways to Guide AGVs Between Stations
• Embedded wire in floor
• Good for applications where paths are not
going to change
• Magnetic Tape on floor
• Requires sensors to detect tape path
• Less expensive and can be modified
• Laser Target navigation
• Requires reflective tape on walls and a laser
transmitter on a rotating turret on the
AGV.
• Good for applications where AGV needs
to adjust path by triangulating position.
• Inertial navigation
• Requires transponders embedded in the
floor
• Extremely accurate (+/- 1 inch)
• Operates in tight aisles or extreme
temperatures.
• Vision Guidance
• Requires cameras (records route and
“replays” route)
• Good for applications where you cannot
modify the environment or infrastructure.
Types and Uses of AGV’s
•
•
•
•
•
•
•
Towing Vehicles
AGVS Unit Load Vehicles
AGVS Pallet Trucks
AGVS Fork Truck
AGVS Hybrid Vehicles
Light Load AGVS
AGVS Assembly Line Vehicles
Types and Uses: Towing Vehicles
• The oldest type of AGV
• Pulls a trailer
• Good for heavy loads
• Range from 8,000 to 60,000 pounds
• Can link multiple trailers
• Increased Safety
Types and Uses: AGVS Unit Load Vehicles
• Load rests over the majority of the
•
•
•
•
vehicle
Interfaces with stands and conveyors
May be loaded by cranes, forklift trucks,
other AGV’s etc.
May communicate between
loading/unloading machine and AGV
(handshake sensor)
More complex steering than towing
AGVs and more expensive
Unit Load Principle
Principle
• Stored or moved as a single entity at
one time, regardless of the number of
individual items that make up the load.
• Less effort and work are required to
collect and move many individual
items as a single load than to move
many items one at a time
AGV Application
• AGV just needs a single flat
platform to transport a unit load,
and unit loads can be stacked on
the platform.
• Does not need a basket (side
barriers)
Types and USES: AGVS Pallet Trucks
• Transport palletized loads to and from
floor level
• 2 general types
• Automatically reverse into pallets
• Operators manually board vehicles and back
them into pallets
• Automatically reversing a guided pallet
truck adds considerable expense.
• Manually loading pallet trucks are more
common.
Types and USES: AGVS Fork Trucks
• “Used when the system requires
automatic pickup and drop off loads
from floor or stand level and where the
heights of load transfer vary at stop
locations.”
• Conveyers or load stands of different
heights can all be serviced
• Most expensive of AGVS types
• Harder to move large loads
• Requires more precise movement.
Types and Uses: AGVS Hybrid Vehicles
• “Adapted from a standard CAT-style
man-aboard truck so that they can run
fully automated or be driven by a fork
truck driver. These can be used for
trailer loading as well as moving
materials around warehouses.”
(Wikipedia)
• Customizable for most load types.
• 25 – 30% cheaper than standard AGV’s
• High Flexibility
Types and USES: Light-load AGVS
• 500 pounds or less
• Transport small parts to individual
work locations
• Trays/baskets
• Good for small and tight areas
• Applications include electronic
fabrication, small assembly
manufacturing and parts kitting
applications
Types and Uses: AGVS Assembly Line Vehicles
• Similar to light load AGVS
• Good for applications involving
serial assembly processes
• Cary subassemblies such as
motors or transmissions
• Allow for parallel operations
• Allow for individual tracking
and measured work rates
• Require extensive planning
COSTS
Level 1: Simple
Manual Vehicle Dispatch, Load/Unload, No
Central Controller, No Host Interface.
Level 2: Medium
Automatic Vehicle Dispatch, Load/Unload,
Central Controller, Product Tracking, Multiple
Path Options.
Level 3: More
Automatic Vehicle Dispatch, Load/Unload,
automatic coupling/uncoupling (applies to
tuggers only), Central Controller, Complex Host
Interface, Ethernet Link, Product Tracking,
Multiple Path Options Multiple Transfer
Heights, etc.
Primary Vendors
•
•
•
•
•
•
Savant Automation, Inc.
America in Motion
Ward Systems, Inc.
Egemin
JBT Corporation
TecnoFerrari/Prella Technologies
Supporting Technologies
Technical Paper: Modelling battery constraints
in discrete event automated guided vehicle
simulations
• Author: R. McHANEY
• Purpose:
• AGV battery usage is frequently omitted in simulation because battery constraints are
mistakingly believed to have minimal impact on throughout and the number of vehicles
required to operate a system, many simulation analysts do not have a full understanding
of how batteries are used to power AGVs, and battery analysis requires additional input
information and varies from vendor to vendor.
• Main Takeaway
• Do not ignore battery considerations. They are important.
Video
• https://www.youtube.com/watch?v=33XpgfppjtE
Standards
ANSI/ITSDF B56.5-2012
- Safety standard for Driverless, Automatic Guided Industrial Vehicles and
Automated Functions of Manned Industrial Vehicles
- Applies to system suppliers, manufacturers, purchasers and users for the
design, construction, application, operation and maintenance of UGVs
Example
• The AGV’s in the figure include load
station 1 where raw parts enter the system
for delivery to any of three production
stations 2,3, and 4. Unload station 5
receives finished parts from the
production stations. Load and unload
times at stations 1 and 5 are each 0.5 min.
Production rates for each workstation are
indicated by the delivery requirements in
Table 10.5. A complicating factor is that
some parts must be transshipped between
stations 3 and 4. Vehicles move in the
direction indicated by the arrow in the
figure. Determine the average delivery
distance, L₂.
Example
9 50 +5 120 +6 205 +9 80 +2 85 +3 170 +8(85)
9+5+6+9+2+3+8
4,360
= 42
Ld=
Ld= 103.8 m
Summary: Main Takeaways
• The type of AGV you use is highly dependent on the layout of the
workspace
• AGVs are highly dependent on specific types of sensors, which depend on
the application and type of navigation that the AGV uses.
Sources
•
•
•
•
•
http://www.agvsystems.com/faqs/
http://www.agvsystems.com/
http://www.mhi.org/agvs/cost-estimating
http://www.agvsystems.com/tow-vehicles/
http://www.jbtcagv.com/en/Solutions/Products/Unit-LoadAutomatic-Guided-Vehicles-AGVs
• http://www.mhi.org/media/news/11614
• http://www.agvsystems.com/agvsbasics/basics-agvs/#fork